Washington state officials said that over 3,000 inmates have been mistakenly released too early from prison since 2002 due to a computer glitch.

Gov. Jay Inslee announced on Tuesday that an error in calculating good time credit by Washington state's Department of Corrections led to the early release of 3,200 convicted offenders over the last 13 years, reports CNN.

According to Inslee, the mistakes began after a 2002 state Supreme Court ruling ordered the Department of Corrections to apply good time credits earned in county jail to state sentences. Subsequently, about 3 percent of inmates in the prison population were given excessive good-behavior credits. Meanwhile, another 3,100 currently incarcerated people were set for inaccurate release dates.

"That this problem was allowed to continue for 13 years is deeply disappointing to me, totally unacceptable and, frankly, maddening," Inslee said in a statement.

Although corrections officials became aware of this problem in December 2012, the solution to the error "was repeatedly delayed," the governor said at the news conference. He only became aware of it last week after a newly hired chief information officer brough up the issue.

"For reasons we still don't yet fully understand, that fix never happened," Inslee said, according to The Associated Press.

Inslee's general counsel, Nicholas Brown, said most of the inmates were released too early by 100 days or less. However, at least one incarcerated convict had a release date that was off by about 600 days.

Correction officials are now working to track down the ex-offenders who were released too early so that state authorities can ensure the ex-offenders will "fulfill their sentences as required by law," officials said. However, most of the affected offenders will not have to be reincarcerated.

"So far Department of Corrections has identified seven offenders that need to be brought back in, and we've brought in five," said Jaime Smith, the spokeswoman for the governor's office.

In the meantime, the governor hired two retired federal prosecutors to conduct an independent review of how the error occurred and why it took over a decade to resolve.

"These were serious errors with serious implications. When I learned of this, I ordered DOC to fix this, fix it fast, and fix it right," the governor said in a statement.

"I have a lot of questions about how and why this happened, and I understand that members of the public will have those same questions. I expect the external investigation will bring the transparency and accountability we need to make sure this issue is resolved," he added.

In addition, Inslee ordered officials to temporary halt releasing any state prisoner "until a hand calculation is done to ensure the offender is being released on the correct date," officials said.

A fix to calculating release dates is expected to be in place by Jan. 7.